Biomedical subjects

An-Long Xu

Publications and source records attributed to An-Long Xu.

14 recordsLinked to original sources

PubMed2003

Recombinant human interleukin-10 inhibits proliferation of vascular smooth muscle cells stimulated by advanced glycation end products and neointima hyperplasia after carotid injury in the rat.

The purposes of this study was to determine the effects of recombinant human interleukin-10 (rhIL-10) on proliferation of vascular smooth muscle cells (VSMCs) stimulated by advanced glycation end products (AGE) and neointima hyperplasia after rat carotid arterial injury. Rat aortic VSMCs were cultured and treated with rhIL-10 or AGE respectively, and then co-treated with rhIL-10 and AGE. Proliferation of VSMCs was quantified by colormetric assay. Cell cycle analysis was performed by flow cytomertry. Sprague-Dawley rats were treated with recombinant human IL-10 (rhIL-10) for 3 d after carotid arteries injury. The ratio of neointima to media area at the site of arterial injury was measured 28 d after balloon injury. The p44/42 MAPK activity was evaluated by the immunoblotting technique using anti-p44/42 phospho-MAPK antibody. Compared to control, AGE stimulated VSMCs proliferation. rhIL-10 alone had no effect on VSMCs growth. With AGE stimulation, rhIL-10, at dose as low as 10 ng/ml, inhibited VSMCs growth (P<0.05). The cell number in G(0)/G(1) phase of AGE and rhIL-10 co-treatment group was higher than that of AGE treatment alone (P<0.01) by flow cytometry analysis. Compared with the control group of neointima hyperplasia in rats, the ratio of neointima to media area of recombinant human IL-10 group was reduced by 45% (P<0.01). The p44/42 MAPK activity was significantly enhanced by AGE. The AGE effects were opposed by rhIL-10. The anti-inflammatory cytokine rhIL-10 inhibits AGE-induced VSMCs proliferation. Recombinant human IL-10 also inhibited neointima hyperplasia after carotid artery injury in rats. The results suggest the possibility that recombinant human IL-10, as a potential therapeutic approach, prevents neointimal hyperplasia.

Animals↗

PubMed2003

Molecular cloning, expression and characterization of three short chain alpha-neurotoxins from the venom of sea snake--Hydrophiinae Hydrophis cyanocinctus Daudin.

Three different genes named sn311, sn316 and sn285 were discovered by large-scale randomly sequencing the high quality cDNA library of the venom glands from Hydrophiinae Hydrophis cyanocinctus Daudin. Sequence analysis showed that these three genes encoded three different short chain alpha-neurotoxins of 81 amino acids, which contained a signal peptide of 21 amino acids and followed by a mature peptide of 60 amino acids. Amino acid comparison reveals that mature peptides of sn311 and sn316 are highly homologous, with the only variance at position 46, which is Lys46 and Ser46, respectively. Whereas the mature peptide of sn285 lacks the most conserved amino acids in short chain alpha-neurotoxins, Asp31 and Arg33. The coding sequences of three neurotoxins were cloned into a thioredoxin (TRX) fusion expression vector (pTRX) and expressed as soluble recombinant fusion proteins in E. coli. After purification, approximately 10 mg/l recombinant proteins with the purity up to 95% were obtained. These three recombinant proteins are designated as rSN311, rSN316 and rSN285, they have a molecular weight of 6.963, 6.920 and 6.756 kDa, respectively, which are similar to those predicted from amino acid sequences. LD50 values of rSN311, rSN316 and rSN285 are 0.0827, 0.095, and 0.0647 mg/kg to mice, respectively. Studies on effects of these recombinant proteins on neuromuscular transmission were carried out, and results indicate that they all can produce prompt blockade of neuromuscular transmission, but display distinct biological activity characteristic individually. The results from UV-circular dichroism (CD) spectra indicate that they share similar secondary structure compared to other identified alpha-neurotoxins, and no significant structural differences in these recombinant proteins are observed.

Amino Acid Sequence↗

PubMed2003

Cloning and characterization of a novel neurotoxin from the sea anemone Anthopleura sp.

A full-length cDNA of neurotoxin (Hk2a) was isolated by RT-PCR of total RNA isolated from tentacles of Anthopleura sp. using degenerate oligonucleotide primers and 3',5'-RACE. The cDNA sequence of Hk2a encoded a polypeptide of 47 amino acids, which lacks a typical N-terminal signal sequences commonly found in proteins that are secreted via endoplasmic reticulum-Golgi pathway, indicating the possibility of secretion via a non-classical pathway. The neurotoxin has a predicted molecular mass of 4.8 kDa and a pI value of 7.62. The amino acid sequence of Hk2a is very similar to Anthopleurin C (Ap-C) and Neurotoxin I (Af I), and shares 95% amino acid sequence similarity to Ap-C. The coding region for the matured Hk2a toxin was cloned into the thioredoxin (TRX) fusion expression vector (pTRX) for the fusion expression in Escherichia coli. The recombinant polypeptide of Hk2a (rHk2a) was purified by the affinity chromatography, 15 mg/l of rHk2a was obtained after the digestion with protease 3C and further purification. The molecular weight of rHk2a (5.078 kDa) obtained by MALDI-TOF was very close to that (5Da) calculated from the sequence. The results of the UV-circular dichroism spectra of rHk2a indicates that its secondary structure is similar to that of Ap-B (), having 61.7% beta-sheet and no alpha-helix. Investigation on pharmacological effects of rHk2a in vitro was undertaken, and it was found that LD(50) of rHk2a was 1.4 mg/kg on NIH mice (i.p.). The rHk2a was demonstrated to increase contracting activity on isolated SD rat atria with the enhancing degree reaching 343.5+/-160.5%. The increase in contractile amplitude reached a plateau value within 3-5 min after addition of this toxin.

Amino Acid Sequence↗

PubMed2003

Comparing the base usage frequency between bacteria DNA double strand.

During the Evolution, effected by select pressure or nature mutation, the compositions of bacteria genomes is various. And many experiences prove that the genes between leading strand and lagging strand is distinctly in copy, transcription and repair. Some scholars presume that the bases distribution is difference between the two strand, to verify the guess, we using the technology of bioinformatics, compare the base usage between the DNA double strand in 17 species bacteria. The result show: 1. there is same bases usage frequency in coding sequence between leading strand and lagging strand 2. There also same bases usage frequency in first codon, second codon and third codon. It suggest that there is a equilibrium between the two strand by the effect of select pressure and nature mutation.

Bacteria↗

PubMed2003

[Association of HLA-DPB1 alleles with chronic myelogenous leukemia in southern Chinese Hans].

To clarify the association between HLA-DPB1 alleles and chronic myelogenous leukemia (CML) in South Chinese, the allelic types of HLA-DPB1 were detected by sequence based typing (SBT) in 86 patients with CML and 82 healthy individuals from Southern China. The results showed that the frequencies of HLA-DPB1 * 1301 and DPB1 * 20011 were higher in patients with CML in comparison with those of healthy individuals. It is concluded that positive association may exist between certain HLA-DPB1 alleles and CML.

Alleles↗

PubMed2002

[Recombinant human interleukin-10 inhibits vascular smooth muscle cell proliferation induced by TNF-alpha].

Vessel injury provokes a release in proinflammatory cytokines that influence vascular smooth muscle cell (VSMC) proliferation. The purposes of this study was to determine the effects of recombinant human interleukin-10 (rhIL-10) on rat vascular smooth muscle cell proliferation and the activity of p44/p42 mitogen-activated protein kinase (MAPK) promoted by tumor necrosis factor-alpha (TNF-alpha). Rat aortic VSMCs were cultured and treated with rhIL-10 or TNF-alpha respectively, and then cotreated with rhIL-10 and TNF-alpha. The proliferation of VSMCs was quantified by colormetric assay. Cell cycle analysis was performed by flow cytometry. The p44/42 MAPK activity was evaluated by the immunoblotting technique using anti-p44/42 phospho-MAPK antibody. Compared to control group, TNF-alpha stimulated significantly VSMC proliferation in TNF-alpha group. rhIL-10 alone had no effect on VSMC growth, but significantly inhibited VSMC proliferation induced by TNF-alpha at a dose of 10 ng/ml. The cell number in G(0)/G(1) phase of TNF-alpha and rhIL-10 co-treatment group was higher than that of TNF- alpha group (P<0.01) by flow cytometry analysis. The p44/42 MAPK activity was significantly enhanced by TNF-alpha and the TNF-alpha effect was opposed by rhIL-10. It is suggested that rhIL-10 can inhibit TNF-alpha induced VSMC proliferation and phosphorylation of p44/42 MAPK.

Animals↗

PubMed2002

Cloning and characterization of an acidic cytolysin cDNA from sea anemone Sagartia rosea.

A full-length cDNA of cytolysin (Src I) was isolated from the tentacle of Sagartia rosea (a representative species in China) by reverse transcription polymerase chain reaction. The cDNA with an open reading frame of 648 bp encodes a precursor protein of 216 amino acids, which contains a prepropeptide of 38 amino acids including a signal peptide of 19 amino acids and a propart of 19 amino acids. Lys-Pro at C-terminus of propart is a cleavage site for proline-endopeptidase-like protease. The mature cytolysin has a molecular mass of 19.6 kDa and a pI value of 4.8. Src I is an acidic cytolysin found in sea anemone and shares 75% amino acid sequence similarity to equinatoxin II (Eqt II). The predicted secondary structure of the mature cytolysin comprises 15% alpha-helix, 45% beta-sheet, and 40% random coil. The characteristic amphiphilic alpha-helix of cytolysin is located at the N-terminus of the processed Src I.

Amino Acid Sequence↗

PubMed2002

Association of HLA-DPB1 gene with endometriosis in women of Guangdong Province in China.

OBJECTIVE: To analyze the hereditary susceptibility in patients with endometriosis by way of genotyping of HLA-DPB1 alleles. METHODS: The allelic types of HLA-DPB1 were detected by sequence-based typing (SBT) in 38 patients with endometriosis and 36 healthy women as the control. RESULT: Significant differences in the frequency of HLA-DRB1 allele was not observed between endometriotic patients and normal subjects. CONCLUSION: HLA-DPB1 allele may not be related to endometriosis.

Adult↗

PubMed2002

[Effects of recombinant sea anemone cytotoxin on vascular smooth muscle cell proliferation in rats].

OBJECTIVE: To observe the effects of recombined sea anemone cytotoxin (rSAC) on vascular smooth muscle cell proliferation in rats rSAC. METHODS: Aortic smooth muscle cells (ASMCs) of rats were cultured in vitro and stimulated with rSAC of different concentrations, and were observed in comparison with the control group. The ratio of cell proliferation was determined with non-radioactive MTS/PES assay. RESULTS: The ratio of cell proliferation rate was 0.802+/-0.055 in the control group, and was 0.115+/-0.014, 0.213+/-0.016, 0.335+/-0.097, 0.663+/-0.060, 0.678+/-0.129, and 0.738+/-0.072 in rSAC groups corresponding to rSAC concentrations of 100, 10, 1 mg/ml and 100, 10, 1 ng/ml respectively. It was shown that rSAC significantly inhibited the cell proliferation when the concentration used was above 100 ng/mg (P<0.05), in a dose-dependent manner as compared with the control group (P<0.05). CONCLUSION: rSAC can significantly inhibit the vascular smooth muscle cell proliferation in rats.

Animals↗

PubMed2002

[The construction of cDNA expression library from the tentacles of Sagartia rosea].

A cDNA expression library of the tentacles of Sagartia rosea was constructed. The cDNA was cloned into eukaryotical expression plasmid pcDNA3. SMART protocol was used for cDNA library construction and bioinformatics analysis was carried out. 71 novel EST clones were obtained from 130 sequences in the library, of which there were 21 full-length clones, including cytolysin genes, flourescent protein, ubiquinol-cytochrome C reductase gene, elongation factor, ferritin gene riboflavin kinase gene, ribosomal protein. This provides a base for further investigating their biological activity and application.

Animals↗

PubMed2001

Identification and Funtional Characterization of Three Postsynaptic Short-chain Neurotoxins from Hydrophiinae, Lapemis hardwickii Gray.

Three cDNA clones, sn12, sn36 and sn160, encoding isoforms of postsynaptic short-chain neurotoxins, were cloned by screening a cDNA library of the venom from Hydrophiinae, Lapemis hardwickii Gray. The sequences of three cDNA clones encoded proteins consisting of 60 amino acid residues. There was only one amino acid substitution among the three isoforms SN12, SN36 and SN160 at the position 46 of mature proteins, and they were Pro(46), His(46) and Arg(46), respectively. The three molecules were expressed in Escherichia coli and the recombinant proteins were characterized. Different LD(50) were obtained, namely 0.0956 mg/kg, 0.3467 mg/kg and 0.2192 mg/kg, when the SN12, SN36 and SN160 were injected into Kunming mice(i.p.). In analgesic effect assayed by the acetic acid-induced writhing method, SN12 and SN160 showed similar analgesic effect, but SN36 had effects significantly different with the other two. Our studies suggested that the amino acid residues on position 46 could affect the combination between the postsynaptic short-chain neurotoxins and the nicotinic acetylchoine receptor, since different amino acid substitution resulted in different biological activities.

Journal Article↗

PubMed2001

Diversity of PLA(2) Genes from Sea Snake Lapemis hardwickii Gray Venom.

Three full-length cDNA from Lapemis hardwickii Gray, (namely PLA(2)-8, PLA(2)-9 and PLA(2)-384), encoding phospholipase A(2) (PLA(2)), were isolated and sequenced. These cDNA sequences were composed of 456 bp, 438 bp and 438 bp, encoding a signal peptide of 27 amino acids and a mature peptide of 125, 119 and 119 amino acids, respectively. The analysis results by computer indicated PLA(2)-8, PLA(2)-9and PLA(2)-384 has a pI of ca. 4.8, 7.8 and 8.4, respectively. Sequence analysis of amino acid and prediction of secondary structure suggested that these isoforms of PLA(2) belong to class I PLA(2) family. PLA(2)-8 was highly homologous (81%) to Notechis scutatus scutatus (Australian tiger snake) PLA(2), PLA(2)-9 and PLA(2)-384 showed fairly high sequence homology (90%) to Enhydrina schistosa (beaked sea snake) PLA(2), indicating that they might have similar functions. These results reflect the diversity of Lapemis hardwickii Gray PLA(2) genes. The successful cloning of these isoenzyme genes of sea snake PLA(2) may provide new information for the study on structure-function relationship of PLA(2) family and its possible molecular mechanism.

Journal Article↗

PubMed2001

Effects of Cyclosporine A and Highly Expressed Bcl-2 on Apoptosis of HL-60 Cells Induced by EGTA.

Effects of mitochondrial permeability transition pore-specific inhibitor cyclosporine A (CsA) and highly expressed Bcl-2 on the apoptosis of HL-60 cells induced by EGTA were studied. Detection of apoptotic peak by flow cytometry, fluorescent microscope observation of chromatin condensation with double staining of PI and Hoechst33342 and DNA ladder analysis all demonstrated that CsA obviously enhanced the apoptosis of HL-60 cells induced by EGTA, while highly expressed Bcl-2 completely blocked it. It is revealed by mitochondrial membrane potential (deltapsi(m)) fluorescent probes rhodamine 123 and CMXRos that the deltapsi(m) decreased in the apoptosis of HL-60 cells induced by EGTA. CsA enhanced the decrease of deltapsi(m), but highly expressed Bcl-2 increased deltapsi(m) of HL-60 cells about 2-fold and completely blocked the decrease of deltapsi(m).

Journal Article↗

PubMed2001

Effect of recombinant human interleukin-10 on the in vitro proliferation of rat vascular smooth muscle cells.

OBJECTIVE: To observe the effects of recombinant human interleukin-10 (rhIL-10) on the proliferation of rat vascular smooth muscle cells (VSMCs) cultured in vitro. METHOD: Aortic VSMCs cultured in vitro were treated with varied doses of rhIL-10 alone or in combination with tumor necrosis factor-alpha (TGF-alpha) or platelet-derived growth factor-BB(PDGF- BB) respectively. The VSMC proliferation was quantified by colormetric assay. RESULTS: Compared with control, both TNF-alpha and PDGF-BB stimulated conspicuous proliferation of VSMCs, but the effect of which was not observed by rhIL-10 treatment alone. In the presence of rhIL-10, the proliferation effects of both TGF-alpha and PDGF-BB on VSMCs were significantly inhibited (P<0.05). CONCLUSION: rhIL-10 can inhibit VSMC proliferation induced by TNF-alpha and PDGF-BB, thus may provide a new therapeutic approach for regulating vascular wall remodeling after vascular injury.

Journal Article↗